The conventional SCSI interface employs a device type code and a serial number to manage a device.
On the other hand, the fiber channel standard requires that a device be managed with a world wide name (WWN). The WWN, which has a data length of eight bytes, is required to be set to a value unique to the port to which the device is connected. Since the device type code and the serial number employed in the conventional SCSI interface do not serve as a value unique to the port, the WWN is required to be newly set.
Further, in the case of using the SCSI interface, a target ID and a logical unit number are specified when the device is accessed. On the other hand, the fiber-channel standard provides that only the logical unit number of the device be specified. That is, in the case of using the fiber-channel interface, each device is required to be assigned a different logical unit number.
Furthermore, the SCSI standard defines a logical unit number “0” as an essential device. Therefore, replacement of a device having the logical unit number “0” makes all the connected devices unusable.